Positive photosensitive resin composition

ABSTRACT

Provided is a positive photosensitive resin composition comprising (A) a polymer which has alicyclic hydrocarbon skeletons and decomposes under the action of an acid to be rendered soluble in alkali, (B) a compound which generates an acid upon irradiation with actinic rays, (C) a nitrogen-containing basic compound, (D) at least one of a fluorine-containing surfactant and a silicon-containing surfactant and (E) a solvent. The composition can exhibit better characteristics when the solvent (E) is a combination of specified solvents.

FIELD OF THE INVENTION

[0001] The present invention relates to a positive photosensitive resincomposition used in a production process of semiconductor devices, suchas IC, production of circuit substrates for liquid crystal, thermal headand the like, and other photo-fabrication processes. To mention indetail, the invention is concerned with a positive photosensitive resincomposition used appropriately for producing semiconductor elements bymeans of micro-lithography utilizing energy beams of short wavelengths,such as far ultraviolet rays, X-rays and electron beams. In particular,the invention relates to a positive photosensitive resin compositionused advantageously for producing semiconductor elements by means ofmicro-lithography utilizing ArF excimer laser.

BACKGROUND OF THE INVENTION

[0002] In recent years the research and development for raising theintegration degree of semiconductor integrated circuits has made rapidprogress and, with the practical use of LSI and VLSI, the minimumpattern width of integrated circuits has reached the level of a sub-halfmicron. Further, the patterns are being fined.

[0003] Under these circumstances, requirements for photo-lithographictechnology applied to fine pattern formation have become severer andseverer. As one of means to aim at fining patterns, it is known toselect light of shorter wavelengths as the exposure light for formingresist patterns.

[0004] For instance, in the production of DRAM having an integrationdegree up to 64 Mega-bit, i-ray (365 nm) of a high-pressure mercury lamphas so far been used as light source. In the mass production of 256Mega-bit DRAM, KrF excimer laser (248 nm) has been put to practical useas a light source instead of i-ray. Further, light sources of shorterwavelengths have been investigated for the purpose of producing DRAMwith an integration degree of 1 Giga-bit or above, and thereby theutilization of ArF excimer laser (193 nm), F₂ excimer laser (157 nm),X-rays and electron beams has been considered effective (Takumi Ueno etal., Short-wavelength Photoresist Materials—Micro-lithography for ULSI,Bunshin Shuppan (1988)).

[0005] In particular, ArF excimer laser is evaluated as the light sourcefor exposure arts in the next generation, and so it is desired todevelop resist materials which are suitable for exposure to ArF excimerlaser and can ensure high sensitivity, high resolution and excellent-dryetching resistance.

[0006] As conventional resist materials for exposure to i-ray and KrFexcimer laser, the resist materials containing aromatic polymers havewidely been used with the intention of ensuring high dry etchingresistance. For instance, there are known novolak resin resist andchemically amplified resist of polyvinylphenol type. However, thearomatic rings introduced for the purpose of conferring dry etchingresistance on resist hardly transmit light in the wavelength region ofArF excimer laser, so that it is difficult for the light to arrive atthe bottom of resist film. Therefore, the conventional resist materialscannot form patterns having satisfactory profile.

[0007] As a solution to a problem concerning the transparency of resist,the use of aromatic ring-free aliphatic polymers, such as polymethylmethacrylate, is known to be acceptable (J. Vac. Sci. Technol., B9, 3357(1991)). However, such polymers are not practicable because sufficientdry etching resistance can hardly be expected therefrom. The greatestproblem which confronts the development of resist materials for exposureto ArF excimer laser is to ensure both improved transparency and highdry etching resistance in the resist film.

[0008] So it was reported in Proc. SPIE, 1672, 66 (1992) that the resistmaterials containing alicyclic hydrocarbon groups instead of aromaticgroups showed dry etching resistance similar to those containingaromatic groups and had weak absorption at 193 nm. As a result, theutilization of such polymers has energetically been studied in recentyears.

[0009] Originally, the application of polymers containing alicyclichydrocarbon groups to resist materials has been attempted from of old.For instance, the norbornene polymers are disclosed in JP-A-60-195542,JP-A-1-217453 and JP-A-2-59751 (the term “JP-A” as used herein means an“unexamined published Japanese patent application”), and variousalkali-soluble resins having cyclic aliphatic hydrocarbon skeletones andmaleic anhydride units are disclosed in JP-A-2-146045.

[0010] Further, the copolymers of norbornene and acrylates protected byacid decomposable groups are disclosed in JP-A-5-80515, the copolymershaving adamantane skeletons in side chains are disclosed inJP-A-4-39665, JP-A-5-265212, JP-A-5-80515 and JP-A-7-234511, thepolymers having side chains to which are attached C₇-C₁₂ aliphaticcyclic hydrocarbon groups containing bridged cyclic hydrocarbon groups,such as tricyclo[5,2,1,02,6]decanedimethylene group,tricyclo-[5,2,1,02,6]decanediyl group, norbornanediyl group,norbornanedimethyl group and adamantanediyl group, are disclosed inJP-A-7-252324 and JP-A-9-221526, and the polymers having side chains towhich are attached tricyclodecanyl groups, dicylopentenyl groups,docyclopentenyloxyethyl groups, norbornyl groups or cyclohexyl groupsare disclosed in JP-A-7-199467.

[0011] Furthermore, the polymers having cyclohexane and isobornylskeletons in their main chains are disclosed in JP-A-9-325498, thepolymers having main chains wherein are introduced various cyclicolefins, e.g., dicycloolefin, are disclosed in JP-A-9-230595,JP-A-9-244247, JP-A-10-10739, WO 97-33198, and European Patents 794,458and 789,278. In addition, JP-A-8-82925 and JP-A-9-230597 disclose thatthe compounds having menthyl or menthyl derivative groups are preferableto the compounds having other terpenoid skeletons.

[0012] Separately from the aforementioned problem concerning resistproperties, the generation of defects (voids) attributable tolithographic processes constitutes a major factor in lowering a yield,which has been a recent big problem to be tackled.

[0013] The development defects, for instance, are said to beattributable to air bubbles generated at the time of serving a developerand micro bubbles due to the gas dissolved in a developer (Hirano etal., The 42th Applied Physical Society Symposium 27p-ZW-9 (1996)). Withthe increase in diameter of wafers and amount of a developer jetted out,the air bubble-control measure becomes a matter of greater importance.As measures to prevent air bubbles, it has been attempted to improve anapparatus so as to softly jet out a developer (See a book, entitled“Contamination Control Techniques for ULSI Production”, p. 41, publishedby Science Forum Co. (1992)) and to reduce air bubbles by addition of adegassing mechanism for dissolved gas. However, these measures are notsuccessful in reducing the defects to a satisfactory level.

[0014] As other measures to reduce development defects, the addition ofa nonionic surfactant to a developer has been devised for improving thewettability of a developer to promote the release of air bubbles, andthe affinity improvement has been attempted by finding out the mostappropriate species and addition amount for the surfactant used innovolak resist (Hakushima et al., The 42th Applied Physical SocietySymposium 27p-ZW-7 (1996)).

[0015] However, these measures are insufficient for the reduction ofdevelopment defects in nonaromatic polymer-utilized ArF laser resist ofchemical amplification type; on the contrary, they sometimes haveadverse effect thereon. Therefore, no guidelines on what measure to takefor reduction of development defects have been drawn up yet. Inaddition, raising the affinity of resist with the intention of reducingdevelopment defects tends to cause deterioration in residual film rateand profile, so that it is very difficult to ensure both reduceddevelopment defects and high quality of resist patterns.

[0016] Further, as reported by, e.g., Proc. SPIE, 1672, 46 (1992), Proc.SPIE, 2438, 551 (1995), Proc. SPIE, 2438, 563 (1995), Proc. SPIE, 1925,14 (1993), J. Photopolym. Sci. Tech., vol. 8, No. 4, 535 (1995), J.Photopolym. Sci. Tech., vol. 5, No. 1, 207 (1992), J. Photopolym. Sci.Tech., vol. 8, No. 4, 561 (1995), and Jpn. J. Appl. Phys., 33, 7023(1994), conventional aromatic polymer-utilized KrF laser positive resistmaterials of chemical amplification type have a problem of sufferingdiffusion of the acid produced therein and deactivation of the acid inthe surface part of the resist by basic impurities in the atmosphere asthe standing period from exposure to heat treatment (PEB) is prolonged,thereby changing the sensitivity and the profile and line width of theresist pattern obtained by development.

[0017] As for the known means to solve such a problem, the arts ofadding amines to aromatic polymer-utilized chemically amplified resistmaterials are disclosed in, e.g., JP-A-63-149640, JP-A-5-249662,JP-A-5-127369, JP-A-5-289322, JP-A-5-249683, JP-A-5-289340,JP-A-5-232706, JP-A-5-257282, JP-A-6-242605, JP-A-6-242606,JP-A-6-266100, JP-A-6-266110, JP-A-6-317902, JP-A-7-120929,JP-A-7-146558, JP-A-7-319163, JP-A-7-508840, JP-A-7-333844,JP-A-7-219217, JP-A-7-92678, JP-A-7-28247, JP-A-8-22120, JP-A-8-110638,JP-A-8-123030, JP-A-9-274312, JP-A-9-166871, JP-A-9-292708,JP-A-9-325496, JP-C-7-508840 (the term “JP-C” as used herein means a“PCT application published in Japanese”), U.S. Pat. No. 5,525,453, U.S.Pat. No. 5,629,134 and U.S. Pat. No. 5,667,938.

[0018] Although the addition of those amines to chemically amplified ArFlaser resist materials using nonaromatic polymers having cyclicaliphatic hydrocarbon skeletons, in analogy with those using aromaticpolymers, surely has an effect on the sensitivity change and the changesin the profile and line width of the resist pattern obtained bydevelopment, it causes a serious deterioration in development defects.Therefore, it has been desired to take some measure to deal with thissituation.

[0019] Furthermore, it has been devised to heighten resolution by theaddition of low molecular weight dissolution inhibitors.

[0020] For instance, JP-A-8-15865 discloses the t-butyl ester ofandrostane as a dissolution inhibitor, and JP-A-9-265177 discloses lowmolecular weight dissolution inhibitors wherein an acid decomposablegroup is attached to a norbornyl, adamantyl, decanyl or cyclohexylgroup. In addition, it is reported in Proc. SPIE, 3049, 84 (1997) thatthe use of t-butyl lithocolate oligomers as dissolution inhibitor canimprove the adhesiveness and the contrast.

[0021] On the other hand, the coating solvents which have generally beenused for conventional positive photoresist materials ofnaphthoquinonediazide/novolak resin type are glycol ethers such as2-methoxyethanol and 2-ethoxyethanol, and acetates thereof such asethylene glycol monomethyl ether acetate and ethylene glycol monoethylether acetate.

[0022] However, the fear that the solvents containing these glycol etherderivatives would have bad influence upon the generative function ofmice was pointed out in 1979, and since then the tests on animals havebeen repeated mainly in western countries. As a result, it wasascertained that those solvents had biological toxicity such asgenerative functional disorder, and reported that those solventsconstitute a potential biological threat to safety of workers (NIOHCurrent Intelligence Buletin, vol. 39, No. 5 (1983)). Further, theEnvironmental Protection Agency (EPA) of America advised to strengthenthe regulation in 1984, and the movement to strengthen the regulationhas been spread.

[0023] Under these circumstances, most of photoresist makers wait forthe development of photoresist products suitable for low-toxicitysolvents free of ethylene glycol ethers.

[0024] With respect to the low-toxicity solvents as substitutes forethylene glycol ethers, there are known the monooxycaroxylates such asethyl lactate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate,ethyl 3-ethoxypropionate (JP-B-3-22619, U.S. Pat. No. 5,238,774,European Patent 211,667) and propylene glycol monomethyl ether acetate(JP-B-3-1659 and U.S. Pat. No. 619,468). The term “JP-B” as used thereinmeans an “examined Japanese patent publication”. Besides these solvents,it was proposed to use cyclopentanone N-hexanol, diethylene glycoldimethyl ether (SEMICONDUCTOR INTERNATIONAL, Vol.4, pp. 132-133 (1988)),2-heptanone (NIKKEI MATERIALS & TECHNOLOGY, Vol. 12, pp. 83-89 (1993))and methyl pyruvate (JP-A-63-220139, JP-A-4-36752 and U.S. Pat. No.5,100,758) as solvents for the positive photoresist compositions ofnaphthoquinonediazide/novolak resin type.

[0025] Similarly, the combination of the above-recited methyl3-methoxypropionate and ethyl 3-ethoxypropionate (JP-A-6-11836) and thecombination of the above-recited ethyl lactate and ethyl3-ethoxypropionate (JP-A-6-308734) are disclosed as the solvents fori-ray or KrF laser resist compositions and chemically amplified positiveresist compositions.

[0026] As mentioned above, many substitute solvents have been proposed,but the toxicity tests (tests of chronic toxicity, generative toxicity,malformation probability, mutation probability, cancer probability andlife's fate) require a long time, and so not all the substitute solventshave proved to be safe.

[0027] After all, the toxicity of ethylene glycol monoethyl etheracetate is supposed to be attributed to the toxicity (malformationprobability) of ethoxyacetic acid which is produced from 2-ethoxyethanolreleased upon the decomposition of the foregoing glycol ether acetate bymetabolism in living things.

[0028] The substitute solvents, e.g., ethyl lactate is supposed to besafe since it is decomposed into lactic acid and ethanol bymetabolism inliving things, and permitted as a food additive. In analogy with ethyllactate, ethyl-3-ethoxypropionate is supposed to be highly safe, becauseit is converted successively into 3-ethoxypropionic acid, ethylmalonicacid and malonic acid by metabolism in living things to produce noalkoxyacetic acid. Similarly, propylene glycol monomethyl ether acetateis reduced to propylene glycol without producing an alkoxyacetic acid,and so the toxicity thereof is ascertained to be much lower than that ofthe corresponding ethylene glycol.

[0029] As mentioned above, the first requirement for photoresistsolvents is low toxicity.

[0030] The second important requirement for photoresist solvents is toensure satisfactory coating characteristics in the resist compositions.

[0031] With the recent elevation of integration degree in LSI, thediameter of wafers has gotten greater. The greater the wafer diameter,the harder it becomes to ensure spin coating uniformity all over thewafer and avoid leaving uncoated part on the wafer to result in adecrease of industrial value.

[0032] For the purpose of improving the coating characteristics ofpositive photoresist compositions of naphthoquinone-diazide/novolakresin type, the addition of fluorine-containing surfactants to knownsolvents for resist compositions, such as ethylene glycol monoethylether, ethylene glycol monoethyl ether acetate, ethylene glycolmonomethyl ether, ethylene glycol monomethyl ether acetate,N,N-dimethylformamide, dioxane, cyclohexanone, cyclopentanone,γ-butyrolactone, ethyl lactate and methyl lactate, is disclosed inJP-A-58-105143, JP-A-58-203434 and JP-A-62-36657, and the combinationsof cyclopentanone and cyclohexane with C₅ to C₁₂ aliphatic alcohols aredisclosed in U.S. Pat. No. 4,526,856 and JP-A-59-231534.

[0033] Further, JP-A-60-24545 discloses that the striation (coatingmarks made when the resist composition is coated on a substrate) isimproved by the combined use of a solvent having a boiling point of60-170° C. and a solvent having a boiling point of 180-350° C. Thegeneration of striation is attributable to natural convection caused ina liquid film by a temperature difference arising between the surfaceand the inner part of the liquid film upon rapid vaporization of thesolvent. The art of preventing the striation by the addition ofsurfactants or the use of mixed solvents as mentioned above is beingestablished.

[0034] Even if the striation can be prevented by the foregoing arts, itfrequently happens that the uniformity of the coating in the diameterdirection of a substrate (unevenness of film thickness) developsproblems. For instance, it was pointed out that, when the resistcomposition using ethyl lactate as a solvent is coated, the resist filmthickness varies widely, compared with the case of using ethylene glycolmonoethyl ether acetate as the resist solvent (NIKKEI MATERIALS &TECHNOLOGY, Vol. 12, p. 87 (1993)).

[0035] It was reported (in Monthly Semiconductor World, Vol. 1, pp.125-128 (1991)) that the aforementioned coating characteristics ofresist compositions suitable for exposure to i-ray or KrF laser hadcorrelations with physical properties of the solvent used therein,including the evaporation speed, the latent heat upon evaporation andthe viscosity. For the purpose of solving this problem, many ideas havebeen come up with. For instance, ethyl lactate is mixed with ethyl3-ethoxypropionate (JP-A-3-504422, U.S. Pat. No. 5,063,138, EuropeanPatent 442,952 and WO 90/05325) , it is mixed with isoamyl acetate orn-amyl acetate (U.S. Pat. No. 5,336,583, European Patent 510,670 andJP-A-5-34918), or it is mixed with anisole and amyl acetate (U.S. Pat.No. 5,128,230).

[0036] The overall uniformity requirement for a chemically amplifiedpositive resist composition coated on a wafer is as severe as or severerthan that for the aforementioned naphthoquinonediazide/novolak resintype of positive resist composition coated on a wafer. This is becausethe chemically amplified positive resist compositions coated on wafershaving great diameters (at least 6 inches) are used for thesemiconductor production in most cases.

[0037] These coating characteristics can be improved to a certain extentby improvement of the coating apparatus, more specifically by optimizingthe atmosphere temperature upon coating, the substrate temperature, thetemperature of resist to be coated, the ventilating condition and so on.However, it is most desirable to ensure uniformity for the resistcoating, irrespective of those conditions of the apparatus.

[0038] Separately from the foregoing problem, another problem developsin some cases. For instance, certain chemically amplified positiveresist compositions separate out fine particles, which cannot beperceived by visual observation, on standing after filtration with amicro-filter, and further come to liberate precipitates when they arestored for a long time.

[0039] In the formation of a resist pattern on a wafer by the use of theresist composition containing such fine particles, it occurs that thefine particles are left on the areas to remove the resist bydevelopment, resulting in the lowering of resolution.

[0040] These fine particles in a chemically amplified positive resistcomposition arise mainly from a photo-acid generator, anacid-decomposable dissolution inhibitor or/and an alkali-soluble resincontaining acid-decomposable groups.

[0041] The mixing with a high boiling point solvent, such asN-methyl-2-pyrrolidone, dimethyl sulfoxide or dimethylformamide, withthe intention of improving the storage stability is certainlyinstrumental in effecting such improvement, but causes deterioration inresist characteristics, including resolution, adhesiveness and heatresistance.

[0042] Therefore, the third requirement for positive photoresistsolvents is to ensure satisfactory storage stability in the resistcompositions, thereby avoiding precipitation of constituents of thephotoresist upon storage.

[0043] Further, the decomposition of a photo-acid generator and anacid-decomposable dissolution inhibitor during storage causes a changein the photoresist sensitivity, and brings a danger of breaking acontainer of the photoresist (a glass vial) due to the inner pressure.Therefore, suitable photoresist solvents are solvents incapable ofinducing the decomposition of photo-acid generators andacid-decomposable dissolution inhibitors.

[0044] The other requirements for photoresist solvents are lowhygroscipicity and, as mentioned in Monthly Semiconductor World, Vol. 1,pp. 135-128 (1991), no deteriorative action on resist characteristics(e.g., sensitivity, resolution, profile, scum, adhesiveness, heatresistance). For example, as described in JP-A-5-173329, ethyl lactatetends to absorb moisture during the preparation and the coating of aphotoresist composition. The photoresist which has absorbed moisturesuffers deterioration in various resist characteristics.

[0045] In addition, it is known that, when a lot of resist solventremains after baking, the resist pattern tends to undergo thermaldeformation (namely, the photoresist tends to suffer deterioration inheat resistance).

[0046] Further, it is known that, when novolak resin is used as abinder, the absorption in the deep UV region (around 248 nm) dependsgreatly on the species of a resist solvent used (S.P.I.E., vol. 1262,pp. 180-187 (1990)). Therefore, the desirable resist solvents aresolvents having slight absorption in the deep UV region. In thechemically amplified positive resist compositions, on the other hand, itis known that the solvent remaining in the resist film produces a greateffect upon the diffusion of acids (as described, e.g., in J. Vac. Sci.Technol. B, Vol. 9, No. 2, pp. 278-289 (1991)). The acid diffusioncauses deterioration in the resolution, the effect of a delay in thepost exposure bake (PEB) (the undesirable phenomenon induced in resistpattern shape and line width by the extension of standing period fromthe exposure to the PEB) and so on. Although it's only natural that thediffusiveness of acids depends on the species of compounds asconstituents of the photoresist, such as a photo-acid generator and anacid-decomposable dissolution inhibitor, the acid diffusion dependsgreatly on the species of a resist solvent used. Accordingly, properlyselecting a resist solvent is especially important for chemicallyamplified resist compositions.

[0047] The chemically amplified resist using a polymer having alicyclichydrocarbon skeletons is exceedingly subject to the aforementioneddevelopment defects, compared with the conventional aromaticrings-containing novolak resin resist and polyhydroxystyrene resist. Asconceivable reasons therefor, the hydrophobic property of the polymerused and the uneven permeation of a developer into the resist film areadduced. Therefore, it is also important to properly select a resistsolvent capable of avoiding the development defects. However, no reportssetting forth guidelines for making a proper selection of resistsolvents have been presented so far.

SUMMARY OF THE INVENTION

[0048] One object of the present invention is to provide a positivephotosensitive resin composition which can have a high residual filmrate, provide excellent resist profile and surmount the problem ofdevelopment defects when the exposure light source used is deepultraviolet rays, particularly ArF excimer laser beams.

[0049] Another object of the present invention is to provide a positivephotosensitive resin composition which can exhibit excellent imageformation characteristics, including a high residual film rate,satisfactory resist profile, high resolution, high sensitivity and highdevelopability, and does not cause the problem of development defectswhen deep ultraviolet rays, particularly ArF excimer laser beams, areused as exposure light source.

[0050] Further object of the present invention is provide a chemicallyamplified resist composition comprising a polymer having alicyclichydrocarbon skeletons, which is useful for the lithography utilizingdeep ultraviolet rays, particularly ArF excimer laser beams, and canfunction as a positive photosensitive resin composition having excellentresist characteristics, satisfactory coating properties, high storagestability in a dissolved condition, high safety and no problem withdevelopment defects.

[0051] As a result of our intensive studies of ingredients to constitutea chemically amplified positive resist composition, it has been foundthat the aforementioned objects can be attained by combining a polymercontaining alicyclic hydrocarbon skeletons in its constitutionalrepeating units, a photo-acid generator, a nitrogen-containing basiccompound, and at least one of a fluorine-containing surfactant and asilicon-containing surfactant, thereby achieving the first compositionaccording to the present invention.

[0052] More specifically, the following (1) to (8) are embodiments ofthe present first composition, and thereby the aforementioned objectsare attained.

[0053] (1) A positive photosensitive resin composition comprising:

[0054] (A) a polymer which has alicyclic hydrocarbon skeletons anddecomposes under the action of an acid to be rendered soluble in alkali,

[0055] (B) a compound which generates an acid upon irradiation withactinic rays,

[0056] (C) a nitrogen-containing basic compound, and

[0057] (D) at least one of a fluorine-containing surfactant and asilicon-containing surfactant.

[0058] (2) A positive photosensitive resin composition comprising:

[0059] (A) a polymer which has bridged alicyclic hydrocarbon skeletonsand decomposes under the action of an acid to be rendered soluble inalkali,

[0060] (B) a compound which generates an acid upon irradiation withactinic rays,

[0061] (C) a nitrogen-containing basic compound,

[0062] (D) at least one of a fluorine-containing surfactant and asilicon-containing surfactant, and

[0063] (E) a solvent;

[0064] wherein the ratio of (B) to (C) by weight is from 5 to 300 andthe ratio of (A) to (D) by weight is from 500 to 20,000.

[0065] (3) A positive photosensitive resin composition according to theforegoing embodiment (1) or (2); further comprising a low molecularacid-decomposable compound which has a molecular weight of 2,000 orbelow and a group capable of decomposing under the action of an acid toincrease its solubility in alkali.

[0066] (4) A positive photosensitive resin composition according to theforegoing embodiment (3), wherein the content of the low molecularacid-decomposable compound is from 0.5 to 20.0 parts by weight per 100parts by weight of the total solids of the composition.

[0067] (5) A positive photosensitive resin composition according to anyof the foregoing embodiments (1) to (4), wherein the compound asComponent (B) is an onium salt.

[0068] (6) A positive photosensitive resin composition according to anyof the foregoing embodiments (1) to (5), wherein the nitrogen-containingbasic compound as Component (C) is an organic amine.

[0069] (7) A positive photosensitive resin composition according to theforegoing embodiment (2), wherein the solvent as Component (E) comprisesat least one solvent selected from the group consisting of ethyllactate, propylene glycol monomethyl ether acetate, propylene glycolmonomethyl ether, propylene glycol monomethyl ether propionate, methyl3-methoxypropionate, ethyl 3-ethoxypripionate and 2-heptanone in anamount of at least 70% by weight based on the total solvent.

[0070] (8) A positive photosensitive resin composition according to anyof the foregoing embodiments (1) to (7), wherein the actinic rays aredeep ultraviolet rays having wavelengths of 220 nm or shorter.

[0071] Further, by our close investigations of ingredients to constitutea chemically amplified positive resist composition, it has been foundthat the aforementioned objects can be attained by combining a polymercontaining alicyclic hydrocarbon skeletons in its constitutionalrepeating units, a photo-acid generator, a nitrogen-containing basiccompound, a fluorine and/or silicon-containing surfactant and particularsolvents, thereby achieving the second composition according to thepresent invention.

[0072] More specifically, the following (9) to (15) are embodiments ofthe present second composition, and thereby the aforementioned objectsare attained.

[0073] (9) A positive photosensitive resin composition comprising:

[0074] (A) a polymer which has alicyclic hydrocarbon skeletons anddecomposes under the action of an acid to be rendered soluble in alkali,

[0075] (B) a compound which generates an acid upon irradiation withactinic rays,

[0076] (C) a nitrogen-containing basic compound,

[0077] (D) a fluorine and/or silicon-containing surfactant, and

[0078] (E) a solvent comprising as a first solvent at least one solventselected from the following group (a) in an amount of 60 to 90% byweight based on the total solvent and as a second solvent a solventselected from the following group (b) in an amount of 10 to 40% byweight based on the total solvent; the group (a) consisting of ethyllactate, propylene glycol monomethyl ether acetate, propylene glycolmonomethyl ether propionate, methyl 3-methoxypropionate and ethyl3-ethoxypropionate, and the group (b) consisting of solvents having aviscosity of not higher than 1 centipoise at 20° C.

[0079] (10) A positive photosensitive resin composition according to theforegoing embodiment (9), wherein the solvent as Component (E) furthercomprises as a third solvent (c) a solvent having a boiling point of notlower than 180° C. and a solubility parameter of at least 12 in anamount of 1 to 20% by weight based on the total solvent.

[0080] (11) A positive photosensitive resin composition according to theforegoing embodiment (10), wherein the third solvent (c) is at least onesolvent selected from the group consisting of γ-butyrolactone, ethylenecarbonate and propylene carbonate.

[0081] (12) A positive photosensitive resin composition according to anyof the foregoing embodiments (9) to (11), wherein the number of carbonatoms forming each of the alicyclic hydrocarbon skeletons present in thepolymer as Component (A) is from 5 to 25.

[0082] (13) A positive photosensitive resin composition according to anyof the foregoing embodiments (9) to (12), wherein thenitrogen-containing basic compound as Component (C) is at least onecompound selected from the group consisting of organic amines, basicammonium salts and basic sulfonium salts.

[0083] (14) A positive photosensitive resin composition according to theforegoing embodiment (9) to (12); further comprising a low molecularacid-decomposable dissolution inhibitive compound which has a molecularweight of 2,000 or below and a group capable of decomposing under theaction of an acid to increase its solubility in alkali.

[0084] (15) A positive photosensitive resin composition according to anyof the foregoing embodiments (9) to (14), wherein the actinic rays aredeep ultraviolet rays having wavelengths of 220 nm or shorter.

[0085] Furthermore, the following (16) to (22) are embodiments of thepresent third composition, and thereby the afore-mentioned objects ofthe present invention are also attained.

[0086] (16) A positive photosensitive resin composition comprising:

[0087] (A) a polymer which has alicyclic hydrocarbon skeletons anddecomposes under the action of an acid to be rendered soluble in alkali,

[0088] (B) a compound which generates an acid upon irradiation withactinic rays,

[0089] (C) a nitrogen-containing basic compound,

[0090] (D) a fluorine and/or silicon-containing surfactant, and

[0091] (E) a solvent comprising (a) ethyl lactate in an amount of 60 to90% by weight based on the total solvent and (b) ethyl3-ethoxypropionate in an amount of 10 to 40% by weight based on thetotal solvent.

[0092] (17) A positive photosensitive resin composition according to theforegoing embodiment (16), wherein the solvent as Component (E) furthercomprises a solvent (c) having a boiling point of not lower than 180° C.and a solubility parameter of at least 12 in an amount of 1 to 20% byweight based on the total solvent.

[0093] (18) A positive photosensitive resin composition according to theforegoing embodiment (17), wherein the solvent (c) is at least onesolvent selected from the group consisting of γ-butyrolactone, ethylenecarbonate and propylene carbonate.

[0094] (19) A positive photosensitive resin composition according to anyof the foregoing embodiments (16) to (18), wherein the number of carbonatoms forming each of the alicyclic hydrocarbon skeletons present in thepolymer as Component (A) is from 5 to 25.

[0095] (20) A positive photosensitive resin composition according to anyof the foregoing embodiments (16) to (19), wherein thenitrogen-containing basic compound as Component (C) is at least onecompound selected from the group consisting of organic amines, basicammonium salts and basic sulfonium salts.

[0096] (21) A positive photosensitive resin composition according to theforegoing embodiment (16) to (20); further comprising a low molecularacid-decomposable dissolution inhibitive compound which has a molecularweight of 2,000 or below and a group capable of decomposing under theaction of an acid to increase its solubility in alkali.

[0097] (22) A positive photosensitive resin composition according to anyof the foregoing embodiments (16) to (21), wherein the actinic rays aredeep ultraviolet rays having wavelengths of 220 nm or shorter.

DETAILED DESCRIPTION OF THE INVENTION

[0098] The compounds usable in the present invention are described belowin greater detail.

[0099] As examples of a polymer usable as the present Component (A)which has alicyclic hydrocarbon skeletons and can have solubility inalkali by undergoing the action of an acid, mention may be made ofhitherto known polymers.

[0100] With respect to the alicyclic part in such a polymer, thesuitable number of carbon atoms forming the ring with a hydrocarbonskeleton is from 5 to 25, and suitable examples of such a ring structureinclude those illustrated below.

[0101] Examples of a polymer usable in the present invention includepolymers comprising constitutional repeating units represented by thefollowing structural formulae (a-1) to (a-15) respectively, wherein thealicyclic hydrocarbon skeletal units constitute the main chain of eachpolymer and the groups capable of decomposing under the action of anacid (hereinafter referred to as acid-decomposable groups) are alsopresent, and polymers comprising constitutional repeating unitsrepresented by the following structural formulae (b-1) to (b-8)respectively, wherein the alicyclic hydrocarbon skeletal units and theacid-decomposable groups are present in the side chains of each polymer.

[0102] Although it is essential for the polymers relating to the presentinvention to contain constitutional repeating units having alicyclichydrocarbon skeletal structures, such as those represented by thefollowing structural formulae (a-1) to (a-15) and (b-1) to (b-8), thepolymers may further contain as copolymerizing component theconstitutional repeating units represented by the following structuralformulae (c-1) to (c-4).

[0103] In each of the foregoing structural units (a-1) to (a-15) and(b-1) to (b-8), A and B each independently represents a hydrogen atom, ahydroxyl group, a carboxyl group, an alkoxycarbonyl group, or asubstituted or unsubstituted alkyl, alkoxy or alkenyl group containing 1to 10 carbon atoms, or they may combine with each other to form a ring.X and Y each independently represents a group capable of decomposingunder the action of an acid.

[0104] In each of the foregoing structural units (b-1) to (b-8) and(c-1) to (c-4), R represents a hydrogen atom or an alkyl group having 1to 3 carbon atoms, such as a methyl group. Z in the foregoing structuralunits (c-1), (c-3) and (c-4) each represents a hydrogen atom, asubstituted or unsubstituted alkyl group containing 1 to 10 carbonatoms, an alkoxycarbonyl group or a group capable of decomposing underthe action of an acid.

[0105] Suitable examples of an alkoxycarbonyl group as mentioned aboveinclude methoxycarbonyl, ethoxycarbonyl and butoxy-carbonyl groups.

[0106] The aforementioned alkyl group containing 1 to 10 carbon atomsincludes unsubstituted or substituted straight-chain, branched andcyclic alkyl groups. More specifically, methyl, ethyl, propyl,isopropyl, n-butyl, t-butyl, cyclopentyl, cyclohexyl, hydroxymethyl andhydroxyethyl groups are included therein.

[0107] Examples of an alkoxy group containing 1 to 10 carbon atomsinclude methoxy, ethoxy, n-butoxy, t-butoxy, propoxy and isopropoxygroups.

[0108] Examples of an alkenyl group containing 2 to 10 carbon atomsinclude allyl, vinyl and 2-propenyl groups.

[0109] In the case of forming a ring by combining A and B, the moietyformed by combining A and B is, e.g., —C(═O)—O—C(═O)—, —C(═O)—NH—C(═O)—or —CH₂—C(═O)—O—C(═O)—.

[0110] The group capable of decomposing under the action of an acid canbe represented by, e.g., —(CH₂)_(n)—COORa or —(CH₂)_(n)—OCORb. Herein,Ra represents a hydrocarbon group having 2 to 20 carbon atoms, withexamples including t-butyl, norbornyl and cyclodecanyl groups. Rbrepresents a tetrahydrofranyl group, a tetrahydropyranyl group, analkoxyethyl group such as ethoxyethyl or isopropoxyethyl, a lactonegroup, or a cyclohexyloxyethyl group. n is 0 or 1.

[0111] Each of the groups as recited above may further have asubstituent group, such as a halogen atom, a cyano group or a nitrogroup.

[0112] Of the alicyclic hydrocarbon skeletons contained in polymersusable as the present Component (A) (which are referred to as Polymers(A) hereinafter), those having a bridged structure are preferred. Thepresence of the bridged structures in Polymers (A) can contribute toimprovement in image characteristics (e.g., resist profile and defocuslatitude). Examples of a constitutional repeating unit having such abridged alicyclic hydrocarbon skeleton include the foregoing structuralunits (a-2) to (a-14), (b-1) to (b-3) and (b-5) to (b-8).

[0113] The Polymers (A) comprising the constitutional repeating unitsrepresented by (a-1) to (a-6) can be prepared by, e.g., subjectingcyclic olefins to ring-opening polymerization in an organic solvent or anon-organic solvent in the presence of a metathesis catalyst, andsubsequently hydrogenating the polymerized product. The ring-opening(co)polymerization can be carried out with ease using the synthesismethods described in, e.g., W. L. Truett et al., J. Am. Chem. Soc., 82,2337 (1960), A. Pacreau, Macromol. Chem., 188, 2585 (1987),JP-A-51-31800, JP-A-1-197460, JP-A-2-42094 and European Patent 0789278.As examples of a metathesis catalyst used therein, mention may be madeof the compounds described in, e.g., Syntheses and Reactions of Polymers(I), pp. 375-381, compiled by Polymer Society of Japan, published byKyoritsu Shuppan in 1992, and JP-A-49-77999, more specifically thecatalytic system constituted of a halogen compound of transition metal,such as tungsten and/or molybdenum, and an organoaluminum compound, andthe catalytic system constituted of those compounds and the thirdcomponent.

[0114] Examples of such tungsten and molybdenum compounds includemolybdenum pentachloride, tungsten hexachloride and tungstenoxytetrachloride. And examples of an organoaluminum compound includetriethylaluminum, triisobutylaluminum, trihexylaluminum, diethylaluminummonochloride, di-n-butylaluminum monochloride, ethylaluminumsesquichloride, diethylaluminum monobutoxide and triethylaluminum-water(1:0.5 by mole). In carrying out the ring-opening polymerization, it isdesirable that the organoaluminum compound be used in an amount of atleast 0.5 mole to 1 mole of tungsten or molybdenum compound.

[0115] Examples of the third component used in the foregoing catalyticsystem for improving the polymerizing activity and so on include water,hydrogen peroxide, oxygen-containing organic compounds,nitrogen-containing organic compounds, halogen-containing organiccompounds, phosphorus-containing organic compounds, sulfur-containingorganic compounds and metal-containing organic compounds. Such acompound as the third component is used in an amount of at most 5 molesper mole of tungsten or molybdenum compound. Such a catalytic system andmonomers are used in an amount of generally from 0.1:100 to 20:100 bymole, though the proportion depends on their species.

[0116] The suitable temperature during the ring-opening (co)polymerization is from −40° C. to +150° C., and it is desirable that thepolymerization be carried out in an atmosphere of inert gas. Examples ofa solvent usable therein include aliphatic hydrocarbons, such aspentane, hexane, heptane and octane; alicyclic hydrocarbons, such ascyclopentane and cyclohexane; aromatic hydrocarbons, such as benzene,toluene and xylene; halogenated hydrocarbons, such as methylenechloride, 1,1-dichloroethane, 1,2-dichloroethane, 1-chloropropane,1-chlorobutane, 1-chloropentane, chlorobenzene, bromobenzene,o-dichlorobenzene and m-dichlorobenzene; and ether compounds, such asdiethyl ether and tetrahydrofuran.

[0117] The polymers produced by the ring-opening (co)polymerization asmentioned above are hydrogenated to yield Polymers (A) usable in thepresent invention. The catalysts usable in the hydrogenation reactionare heterogeneous catalysts and homogeneous catalysts used for generalhydrogenation reaction of olefinic compounds.

[0118] For instance, each of such heterogeneous catalysts is a solidcatalyst comprising a precious metal catalyst, such as palladium,platinum, nickel, ruthenium or rhodium, supported by a carrier such ascarbon, silica, alumina or titania. And those homogeneous catalystsinclude nickel naphthenate/triethyl-aluminum, nickelacetylacetonate/triethylaluminum, cobalt octenate/n-butyllithium,titanocene dichloride/diethyl-aluminum monochloride, and rhodiumcatalysts, such as rhodium acetate andchlorotris(triphenylphosphine)rhodium.

[0119] Of these catalysts, the heterogeneous catalysts are advantageousover the others, because they have high reactivity, can be removed withease after reaction and leave no stain on polymers produced.

[0120] The hydrogenation reaction can be carried out at a temperaturefrom 0° C. to 200° C., preferably from 20° C. to 180° C., in a hydrogengas atmosphere of from ordinary pressure to 300 atmospheric pressure,preferably from 3 to 200 atmospheric pressure. The hydrogenation rate isgenerally at least 50%, preferably at least 70%, more preferably atleast 80%. When the hydrogenation rate is lower than 50%, the polymersproduced have undesirable influence upon thermal stability and storagestability of the resulting resist.

[0121] The polymers comprising the constitutional repeating units (a-7)to (a-15) as illustrated above can be synthesized, e.g., by radical(co)polymerization of alicyclic hydrocarbon monomers in the presence ofan effective amount of free radical polymerization initiator. Morespecifically, they can be synthesized using the methods described in,e.g., J. Macromol. Sci. Chem., A-5(3) 491 (1971), ibid., A-5(8) 1339(1971) , Polym. Lett., Vol. 2, 469 (1964), U.S. Pat. Nos. 3,143,533,3,261,815, 3,510,461, 3,793,510 and 3,703,501, and JP-A-2-146045.

[0122] Suitable examples of an initiator used in the radical(co)polymerization include 2,2′-azobis(2-methylpropane-nitrile), benzoylperoxide and dicumyl peroxide. The initiator concentration is generallyfrom 0.01 to 10% by weight, preferably from 0.1 to 5% by weight, basedon the total weight of monomers. The polymerization temperature can bewidely changed. Specifically, it is generally from room temperature to250° C., preferably from 40 to 200° C., more preferably from 60 to 160°C.

[0123] It is desirable that the polymerization or copolymerization becarried out in an organic solvent. The organic solvents capable ofdissolving monomers at the prescribed temperature, and the polymersproduced as well, are suitably used therein. The suitable solvents,though depend on the species of monomers to be copolymerized, includearomatic hydrocarbons, such as toluene; aliphatic esters, such as ethylacetate, and aromatic esters; and aliphatic ethers, such astetrahydrofuran.

[0124] After running the reaction for the prescribed time, it isdesirable to carry out the distillation under reduced pressure andpurification for the purpose of separating the polymer obtained from themonomers remaining unreacted, the solvent used and so on.

[0125] The polymers having the constitutional repeating units (b-1) to(b-8) or the polymers containing the copolymerizing components (c-1) to(c-4) can be synthesized by radical (co)polymerization in the presenceof an effective amount of free radical initiator.

[0126] The suitable proportion of the constitutional units havingalicyclic skeletons is at least 10 mole %, preferably at least 20 mole%, more preferably at least 30 mole %, to the total constitutional unitsin Polymer (A).

[0127] On the other hand, the suitable proportion of the constitutionalunits having acid-decomposable groups is from 10 to 90 mole %,preferably from 15 to 85 mole %, more preferably from 20 to 80 mole %,to the total constitutional units in Polymer (A).

[0128] For the polymer used in the present invention, it is desirablethat the proportion of a copolymerizing component as represented by(c-1) to (c-4) be from 3 to 60 mole %, preferably from 5 to 55 mole %,more preferably from 10 to 50 mole %, to the total constitutionalrepeating units.

[0129] The suitable weight-average molecular weight of Polymer (A) isfrom 1,500 to 100,000, preferably from 2,000 to 70,000, particularlypreferably from 3,000 to 50,000. When the polymer (A) has a molecularweight lower than 1,500, the resulting composition cannot havesufficient dry etching resistance, heat resistance and adhesiveness to asubstrate; while the molecular weight is higher than 100,000, the resistsensitivity is lowered. The suitable molecular weight distribution(Mw/Mn) is from 1.0 to 6.0, preferably from 1.0 to 4.0. The smallerMw/Mn value the polymer (A) has, the higher heat resistance and thebetter image properties (e.g., resist profile, defocus latitude) can beobtained. In addition, the presence of unreacted monomers in the polymerproduct is undesirable, because it causes deterioration in dry etchingresistance and a drop in transmittance of the resist film. Therefore, itis desirable that the proportion of unreacted monomers in the polymerproduct be lowered to 2% by weight at the most, preferably 1% by weightor below.

[0130] Additionally, the weight-average molecular weight and molecularweight distribution (Mw/Mn) of Polymer (A) are determined as polystyreneequivalents by gel permeation chromatography equipped with a refractiveindex detector.

[0131] The content of Polymer (A) in the present positive photosensitiveresin composition is from 50 to 99.7% by weight, preferably from 70 to99% by weight, on a solids basis.

[0132] The present positive photosensitive resin composition can containpolymers other than Polymer (A), if needed. The suitable content ofother polymers is not higher than 30 parts by weight, preferably nothigher than 20 parts by weight, more preferably not higher than 10 partsby weight, particularly preferably not higher than 5 parts by weight,per 100 parts by weight of Polymer (A).

[0133] As the foregoing other polymers, any polymers may be contained inthe present composition, provided that they are compatible with Polymer(A) as an alicyclic polymer according to the present invention.Specifically, poly(p-hydroxystyrene), hydrogenatedpoly(p-hydroxystyrene) and novolak resin.

[0134] Secondly, the compounds which decompose upon irradiation withactinic rays to generate an acid are illustrated below, which are usableas Component (B) of the present positive photosensitive resincomposition (which are referred to as Photo-acid Generator (B)hereinafter).

[0135] Examples of Photo-acid Generator (B) used in the presentinvention include photo initiators of photo cationic polymerization,photo initiators of photo radical polymerization, photo decolorants ofdyes, photo discoloration agents and photo-acid generators known in thefield of micro photoresist to generate acids upon irradiation withultraviolet rays, deep ultraviolet rays, XrF excimer laser beams, ArFexcimer laser beams, electron beams, X-rays, molecular beams or ionbeams. Two or more agents selected properly from the above-recited onesmay be used as a mixture, too.

[0136] Additionally, the concept of the term, “actinic rays” used in thepresent invention is broad, and includes the radiant rays as recitedabove.

[0137] The Photo-acid Generator (B) has no particular restriction,provided that it can be dissolved in organic solvents, which aredescribed later, used for the present positive photosensitive resincomposition. However, it is desirable that the Photo-acid Generator (B)be a photo-acid generator capable of generating an acid upon irradiationwith light of wavelengths of 220 nm or shorter. Such photo-acidgenerators may be used alone or as a mixture of two or more thereof, orin combination with an appropriate sensitizer.

[0138] Examples of a photo-acid generator usable as Photo-acid Generator(B) include the triphenylsulfonium salt derivatives described in J. Org.Chem., Vol. 43, No. 15, 3055 (1978), and the other onium salts(including sulfonium salts, iodonium salts, phosphonium salts, diazoniumsalts and ammonium salts) disclosed in Japanese Patent Application No.9-279071.

[0139] As examples of an onium salt, mention may be made ofdiphenyliodonium triflate, diphenyliodonium pyrenesulfonate,diphenyliodonium dodecylbenzenesulfonate, triphenylsulfonium triflate,triphenylsulfonium hexafluoroantimonate, diphenyliodoniumhexafluoroantimonate, triphenylsulfonium naphthalenesulfonate,triphenylsulfonium camphorsulfonate, (4-methoxyphenyl)phenyliodoniumtrifluoromethanesulfonate and bis(t-butylphenyl)iodoniumtrifluoromethanesulfonate.

[0140] Further, the diazodisulfones and diazoketosulfones disclosed inJP-A-3-103854, JP-A-3-103856 and JP-A-4-1210960, the iminosulfonatesdisclosed in JP-A-64-18143 and JP-A-2-245756 and the disulfonesdisclosed in JP-A-2-71270 can be used to advantage. Furthermore, thepolymers having groups generating acids upon exposure to light in theirmain or side chains as disclosed in, e.g., U.S. Pat. No. 3,849,137,JP-A-63-26653, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452,JP-A-62-153853 and JP-A-63-146029 can also be used. In addition, the2-oxocyclohexyl group-containing aliphatic alkylsulfonium salts and theN-hydroxysuccinimide sulfonates disclosed in JP-A-7-25846, JP-A-7-28237,JP-A-7-92675 and JP-A-8-27120, and the sulfonium salts described in J.Photopolym. Sci. Tech., Vol. 7, NO. 3, 423 (1994) can also be used toadvantage. These photo-acid generators are used alone or as a mixture oftwo or more thereof.

[0141] Of these photo-acid generators, the onium salts are preferredover the others because they can ensure good sensitivity and resolutionin the resulting resist.

[0142] With respect to the first composition, the proportion of such acompound as to generate an acid upon irradiation with actinic rays(Component (B)) is generally from 0.001 to 40% by weight, preferablyfrom 0.01 to 20% by weight, more preferably from 0.1 to 15% by weight,particularly preferably from 0.5 to 10% by weight, based on the totalweight (on a solids basis) of the present photosensitive resincomposition. With respect to the second and third compositions, theproportion of Component (B) is generally from 0.001 to 40% by weight,preferably from 0.01 to 20% by weight, more preferably from 0.1 to 5% byweight based on the total weight (on a solids basis) of the composition.When the proportion of Photo-acid Generator (B) is lower than 0.001% byweight, the sensitivity is lowered; while, when it is higher than 40% byweight, the resulting resist shows too high absorption of light, andthereby the profile is deteriorated and the process margin, particularlybake margin, is rendered narrow.

[0143] Thirdly, the nitrogen-containing basic compounds contained asComponent (C) in the present positive photosensitive resin composition(which are referred to as Basic Compound (C) hereinafter) areillustrated below.

[0144] As Basic Compound (C), organic amines, basic ammonium salts andbasic sulfonium salts can be employed in terms of obtaining highsensitivity, high resolution and excellent profile, so far as they causeno deterioration in sublimation and resist properties. Of such basiccompounds, organic amines are preferred over the others because they canensure excellent image quality.

[0145] Secifically, usable basic compounds are those disclosed in, e.g.,JP-A-63-149640, JP-A-5-249662, JP-A-5-127369, JP-A-5-289322,JP-A-5-2496832, JP-A-5-289340, JP-A-5-232706, JP-A-5-257282,JP-A-6-242605, JP-A-6-242606, JP-A-6-266100, JP-A-6-266110,JP-A-6-317902, JP-A-7-120929, JP-A-7-146558, JP-A-7-319163,JP-A-7-508840, JP-A-7-333844, JP-A-7-219217, JP-A-7-92678, JP-A-7-28247,JP-A-8-22120, JP-A-8-110638, JP-A-8-123030, JP-A-9-274312,JP-A-9-166871, JP-A-9-292708, JP-A-9-325496, JP-C-7-508840, and U.S.Pat. Nos. 5,525,453, 5,629,134 and 5,667,938.

[0146] Suitable examples of a nitrogen-containing basic compound asComponent (C) include 1,5-diazabicyclo[4.3.0]-5-nonene,1,8-diazabicyclo[5.4.0]-7-undecene, 1,4-diazabicyclo[2.2.2]octane,4-dimethylaminopyridine, 1-naphthylamine, piperidine,hexamethylenetetramine, imidazoles, hydroxypyridines, pyridines,4,4′-diaminodiphenylether, pyridinium p-toluenesulfonate,2,4,6-trimethylpyridinium p-toluenesulfonate, tetramethylammoniump-toluenesulfonate, tetrabutylammonium lactate, triethylamine andtributylamine.

[0147] Of these compounds, organic amines such as1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]-7-undecene,1,4-diazabicyclo-[2.2.2]octane, 4-dimethylaminopyridine,1-naphthylamine, piperidine, hexamethylenetetramine, imidazoles,hydroxy-pyridines, pyridines, 4,4′-diaminodiphenylether, triethylamineand tributylamine are advantageous.

[0148] With respect to the first composition, the content of BasicCompound (C) is generally from 0.001 to 10 parts by weight, preferablyfrom 0.001 to 5 parts by weight, more preferably from 0.001 to 0.5 partsby weight, per 100 parts by weight of the composition (on a solidsbasis). With respect to the second and third compositions, the contentof Basic Compound (C) is generally from 0.001 to 10 parts by weight,preferably from 0.01 to 5 parts by weight, per 100 parts by weight ofthe composition (on a solids basis). When the content is less than 0.001parts by weight, the addition of Component (C) cannot producesatisfactory effect; while, when it is increased beyond 10 parts byweight, the sensitivity and the developability in the unexposed areashow a tendency to considerably deteriorate. The compounds recited aboveas Basic Compound (C) can be used alone or as a mixture of two or morethereof.

[0149] The suitable ratio of the foregoing Photo-acid Generator (B) tothe foregoing nitrogen-containing Basic Compound (C) ((B)/(C) ratio) inthe present composition is from 5 to 300 by weight, preferably from 10to 200 by weight. When the (B)/(C) ratio is controlled to the aforesaidrange, the resist sensitivity and the resolution are improved and thedependency of the pattern line width on the post exposure drawn-outperiod (PED dependency) is reduced. In other words, the improvement inresist sensitivity and resolution and the reduction of PED dependencyare compatible with each other when the Components (B) and (C) are mixedwithin the limits of the ratio mentioned above.

[0150] Fourthly, the fluorine and/or silicon-containing surfactantswhich can be contained as Component (D) in the present positivephotosensitive resin composition are illustrated below.

[0151] In the present photosensitive resin composition, any or at leasttwo of fluorine-containing surfactants, silicon-containing surfactantsand surfactants containing both fluorine and silicon atoms can becontained.

[0152] Examples of a surfactant usable as Component (D) include thesurfactants disclosed in JP-A-62-36663, JP-A-61-226746, JP-A-61-226745,JP-A-62-170950, JP-A-63-34540, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432and JP-A-9-5988. Further, the following commercially producedsurfactants can be used as they are.

[0153] As examples thereof, mention may be made of the fluorine and/orsilicon-containing surfactants available in the following trade names,EFtop EF301 and EF303 (produced by Shin-Akita Kasei K.K.), Florad FC430,431 (produced by Sumitomo 3M Inc.), Megafac F172, F173, F176, F189, R08(produced by Dainippon Ink & Chemicals, Inc.) and Surflon S-382, SC 101,102, 103, 104, 105, 106 (produced by Asahi Glass Co., Ltd.). Inaddition, the polysiloxane polymer KP-341 (produced by Shin-EtsuChemical Co., Ltd.) can also be used as silicon-containing surfactant.

[0154] With respect to the first composition, the amount of Surfactant(D) mixed is generally from 0.001 to 2 parts by weight, preferably from0.003 to 0.10 parts by weight, per 100 parts by weight of solids in thecomposition. With respect to the second and third compositions, theamount of Surfactant (D) mixed is generally from 0.01 to 2 parts byweight, preferably from 0.01 to 1 parts by weight, per 100 parts byweight of solids in the composition.

[0155] Those surfactants can be used alone or as a mixture of two ormore thereof.

[0156] Further, it is desirable in the present composition that theratio of Polymer (A) to Surfactant (D) ((A)/(D) ratio) be from 500 to20,000 by weight, preferably from 1,000 to 15,000 by weight. Bycontrolling the (A)/(D) ratio to the foregoing range, thedevelopability, the line-width reproducibility and the uniformity incoated film thickness are improved.

[0157] Although no clear reason why the present positive photosensitiveresin composition is especially effective for development defects can beset forth, such a special effect can be supposed to be developed by thecombined use of Basic Compound (C) and particular Surfactant (D). Thisis because the image quality, such as profile, becomes unsatisfactorywhen the Basic Compound (C) is used in combination with a surfactantother than Surfactant (D), e.g., a nonionic surfactant not containing afluorine atom or a silicon atom.

[0158] The present positive photosensitive resin composition can furthercontain a low molecular acid-decomposable compound, if needed, which hasa molecular weight of not higher than 2,000 and a group capable ofdecomposing under the action of an acid and can increase its solubilityin alkali under the action of an acid.

[0159] Examples of such a low molecular acid-decomposable compoundinclude the acid-decomposable group-containing alicyclic compounds, suchas cholic acid derivative, dehydrocholic acid derivatives, deoxycholicacid derivatives, lithocholic acid derivative, ursocholic acidderivatives and abietic acid derivatives, and the acid-decomposablegroup-containing aromatic compounds, such as naphthalene derivatives, asdescribed in Proc. SPIE, 2724, 355 (1996), JP-A-8-15865, U.S. Pat. Nos.5,310,619 and 5,372,912, and J. Photopolym. Sci. Tech., Vol. 10, No. 3,511 (1997).

[0160] Furthermore, the low molecular acid-decomposable dissolutioninhibitive compounds disclosed in JP-A-6-51519 can be added in such anamount as not to lower the transmittance at 220 nm, and1,2-naphthoquinonediazide compound can also be used.

[0161] In a case where the foregoing low molecular acid-decomposabledissolution inhibitive compound is used in the first composition, thecontent thereof is generally from 0.5 to 50 parts by weight, preferablyfrom 0.5 to 40 parts by weight, more preferably from 0.5 to 30 parts byweight, particularly preferably from 0.5 to 20.0 parts by weight, per100 parts by weight of photosensitive resin composition (on a solidsbasis). In a case where the foregoing low molecular acid-decomposabledissolution inhibitive compound is used in the second and thirdcompositions, the content thereof is generally from 1 to 50 parts byweight, preferably from 3 to 40 parts by weight, more preferably from 5to 30 parts by weight, per 100 parts by weight of photosensitive resincomposition (on a solids basis).

[0162] The addition of such a low molecular acid-decomposabledissolution inhibitive compound can produce not only further improvementin the aforementioned development defects, but also betterment in dryetching resistance.

[0163] In addition, the present positive photosensitive resincomposition can contain compounds capable of promoting the dissolutionin a developer, anti-halation agents, plasticizers, surfactants,photosensitizers, adhesion aids, cross-linking agents, photo-basegenerators and so on, if desired.

[0164] As examples of a compound capable of promoting the dissolution ina developer, which can be used in the present invention, mention may bemade of the low molecular compounds having molecular weight of nothigher than 1,000 as disclosed in JP-A-3-206458, such as compoundscontaining at least two phenolic hydroxyl groups per molecule, naphtholssuch as 1-naphthol, compounds containing at least one carboxyl group permolecule, carboxylic acid anhydrides, sulfonamide compounds andsulfonylimide compounds.

[0165] The proportion of such a dissolution promoting compound admixedis preferably 30% by weight or below, more preferably 20% by weight orbelow, based on the total weight of the composition (on a solids basis).

[0166] Suitable anti-halation agents are compounds capable of absorbingthe radiant rays irradiated, with examples including substitutedbenzenes, such as fluorene, 9-fluorenone and benzophenone; andpolycyclic aromatic compounds, such as anthracene,anthracene-9-methanol, anthracene-9-carboxyethyl, phenanthrene, peryleneand azulene. Of these compounds, polycyclic aromatic compounds arepreferred in particular. These anti-halation agents can reduce thereflected light from a substrate to lessen the influence of multiplereflection inside the resist film, and thereby the effect of standingwave improvement is developed.

[0167] For the purpose of improving the coating suitability anddevelopability of the present photosensitive resin composition, nonionicsurfactants can be used together.

[0168] Examples of a nonionic surfactant usable for such a purposeinclude polyoxyethylene lauryl ether, polyoxyethylene stearyl ether,polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl etheer,polyethylene glycol dilaurate, polyethylene glycol distearate,polyoxyethylene sorbitane monostearate and sorbitane monolaurate.

[0169] For the purpose of elevating the rate of acid generation byexposure, photosensitizers can be added. Suitable examples of such aphotosensitizer include benzophenone,p,p′-tetramethyldiaminobenzophenone, 2-chlorothioxanthone, anthrone,9-ethoxyanthracene, pyrene, phenothiazine, benzil, benzoflavin,acetophenone, phenanthrene, benzoquinone, anthraquinone and1,2-naphthoquinone. These photosensitizers can also be used as theanti-halation agents as mentioned above.

[0170] In general, the first photosensitive resin composition isprepared in the form of a solution by dissolving the above-illustratedcomponents in an appropriate solvent and then filtering through a filterhaving a pore size of the order of 0.05 to 0.2 μm. Examples of a solventappropriately used therein include ethylene glycol monoethyl etheracetate, cyclohexanone, 2-heptanone, propylene glycol monomethyl ether,propylene glycol monomethyl ether acetate, propylene glycol monomethylether propionate, propylene glycol monoethyl ether acetate, methyl3-methoxypropionate, ethyl 3-ethoxypropionate, methylβ-methoxyisobutyrate, ethyl butyrate, propyl butyrate, methyl isobutylketone, ethyl acetate, isoamyl acetate, ethyl lactate, toluene, xylene,cyclohexyl acetate, diacetone alcohol, N-methylpyrrolidone,N,N-dimethylformamide, γ-butyrolactone and N,N-dimethylacetamide. Thesesolvents can be used alone or as a combination of two or more thereof.From the viewpoint of ensuring satisfactory solubility, coatingsuitability on a substrate and storage stability for the photosensitiveresin composition, it is desirable that at least 70% by weight of thetotal solvents used be at least one solvent selected from the groupconsisting of ethyl lactate, propylene glycol monomethyl ether acetate,propylene glycol monomethyl ether, propylene glycol monomethyl etherpropionate, methyl 3-methoxy-propionate, ethyl 3-ethoxypropionate and2-heptanone.

[0171] In addition, it is desirable that the water content in thesolvents used be as low as possible, because water has adverse effect onresist characteristics.

[0172] Further, it is desirable that the content of impurities, such asmetals and chlorine ion, in the present photosensitive resin compositionbe reduced to 100 ppb or below. If the content of those impurities isnot low, troubles such as poor workings, defects and yield drop arecaused during the production of semiconductor devices.

[0173] Next, the solvents used as Component (E) in the secondcomposition according to the present invention are illustrated below.

[0174] The first solvent (a) used in the present second composition isat least one solvent selected from the group consisting of ethyllactate, propylene glycol monomethyl ether acetate, propylene glycolmonomethyl ether propionate, methyl 3-methoxy-propionate and ethyl3-ethoxypropionate. Of these solvents, ethyl lactate and propyleneglycol monomethyl ether acetate are preferred in particular.

[0175] The first solvent (a) is used in an amount of from 60 to 90% byweight, preferably from 60 to 85% by weight, more preferably from 65 to80% by weight, based on the total solvents as component (E).

[0176] The second solvent (b) used in the present second composition isa solvent having viscosity of 1 centipoise at the highest, preferably0.9 centipoise at the highest, at 20° C. Any solvents can be used as thesecond solvent (b) so far as they meet the aforesaid viscosityrequirement. Examples of an organic solvent having such viscosityinclude methyl acetate, ethyl acetate, propyl acetate, isopropylacetate, butyl acetate, isobutyl acetate, methyl ethyl ketone, methylamyl ketone and methyl isobutyl ketone. Of these solvents, butyl acetateis preferred in particular. These solvents can be used alone, as amixture of two or more thereof.

[0177] The second solvent (b) is used in an amount of from 10 to 40% byweight, preferably from 10 to 30% by weight, more preferably from 10 to25% by weight, based on the total solvents as component (E).

[0178] The sum total of the first solvent (a) and the second solvent (b)desirably comprises at least 70% by weight of the total solvents asComponent (E). When the proportion is less than 70% by weight, itsometimes occurs that the objects of the present invention cannot befully achieved.

[0179] In addition to the first solvent (a) and the second solvent (b),it is desirable to use the third solvent (c) in the present secondcomposition. The third solvent (c) is a solvent having a boiling point(b.p.) of 180° C. or above, preferably 185° C. or above, and asolubility parameter (SP value) of at least 12, preferably at least12.4, and such a solvent is preferably used in an amount of from 1 to20% by weight, more preferably from 3 to 10% by weight, based on thetotal solvents as Component (E).

[0180] The addition of the third solvent (c) can produce an appreciableimprovement in development defects. However, the addition in an amounthigher than 20% by weight causes deterioration in adhesiveness to asubstrate.

[0181] Examples of a solvent usable as the third solvent (c) includeγ-butyrolactone (b.p.: 190° C., SP value: 12.6), propylene carbonate(b.p.: 242° C., SP value: 13.3), ethylene carbonate (b.p.: 239° C., SPvalue: 14.7), N,N-dimethylimidazolinone (b.p.: 200° C., SP value: 12.4)and dimethyl sulfoxide (b.p.: 189° C., SP value: 13.0). Of thesesolvents, γ-butyrolactone, propylene carbonate and ethylene carbonateare preferred in particular with respect to the achievement of thepresent effects.

[0182] Although it is desirable to use the solvents recited above asComponent (E), other solvents may be used together in such an amount asnot to mar the present effects, specifically not higher than 5% byweight.

[0183] As the other solvents, cyclohexanone, propylene glycol monomethylether, methyl β-methoxyisobutyrate, ethyl butyrate, propyl butyrate,diacetone alcohol, N-methylpyrrolidone and so on are usable.

[0184] Now, the solvents used as Component (E) in the third compositionaccording to the present invention are illustrated.

[0185] The Component (E) of the third composition comprises (a) ethyllactate and (b) ethyl 3-ethoxypropionate. The ethyl lactate (a) as themain solvent is used in an amount of from 60 to 90% by weight,preferably from 60 to 85% by weight, more preferably from 65 to 80% byweight, based on the total solvents used as Component (E).

[0186] The proportion of ethyl 3-ethoxypropionate (b) used incombination with ethyl lactate (a) in the Component (E) is from 10 to40% by weight, preferably from 10 to 30% by weight, more preferably from10 to 25% by weight.

[0187] The sum total of ethyl lactate (a) and ethyl 3-ethoxypropionate(b) desirably comprises at least 70% by weight of the total solvents asComponent (E). When the proportion is less than 70% by weight, itsometimes occurs that the objects of the present invention cannot befully achieved.

[0188] In addition to the foregoing solvents (a) and (b), it isdesirable to use another solvent (c) in the present third composition.The solvent (c) is a solvent having a boiling point of 180° C. or above,preferably 185° C. or above, and a solubility parameter (SP value) of atleast 12, preferably at least 12.4, and such a solvent is desirably usedin an amount of from 1 to 20% by weight, preferably from 3 to 15% byweight, based on the total solvents as Component (E).

[0189] The addition of the solvent (c) can produce an appreciableimprovement in development defects. However, the addition in an amounthigher than 20% by weight causes deterioration in adhesiveness to asubstrate.

[0190] Examples of a solvent (c) include γ-butyrolactone (b.p.: 190° C.,SP value: 12.6), propylene carbonate (b.p.: 242° C., SP value: 13.3),ethylene carbonate (b.p.: 239° C., SP value: 14.7),N,N-dimethylimidazolinone (b.p.: 200° C., SP value: 12.4) and dimethylsulfoxide (b.p.: 189° C., SP value: 13.0). Of these solvents,γ-butyrolactone, propylene carbonate and ethylene carbonate arepreferred in particular with respect to the achievement of the presenteffects.

[0191] These solvents (c) can be used alone or as a mixture of two ortwo thereof.

[0192] Although it is desirable to use the solvents recited above asComponent (E), other solvents may be used together in such an amount asnot to mar the present effects, specifically not higher than 5% byweight.

[0193] Examples of other solvents usable for Component (E) includecyclohexanone, 2-heptanone, propylene glycol monomethyl ether, propyleneglycol monomethyl ether acetate, propylene glycol monomethyl etherpropionate, propylene glycol monoethyl ether acetate, methyl3-methoxy-propionate, methyl β-methoxyisobutyrate, ethyl butyrate,propyl butyrate, methyl isobutyl ketone, ethyl acetate, isoamyl acetate,diacetone alcohol and N-methylpyrrolidone.

[0194] Each of the photosensitive resin compositions according to thepresent invention is coated on a substrate by means of an appropriatecoating apparatus, such as a spinner or a coater, subjected to pre-bake(heating prior to exposure), exposed to light of wavelengths of nolonger than 220 nm via the desired mask, subjected to PEB (post-exposurebake), and then developed to provide resist patterns of good quality.

[0195] The substrate used herein may be any of substrates generally usedin semiconductor devices and other manufacturing apparatus, withexamples including a silicon substrate, a glass substrate andnon-magnetic ceramic substrate. On such a substrate, an additionallayer, e.g., a silicon oxide layer, a wiring metal layer, a layerinsulation film, a magnetic layer or a reflection inhibitive film layer,may be present, if desired; and also various wiring and circuits may bebuilt into such a substrate. Further, those substrates may undergohydrophobicity-conferring treatment according to a conventional methodfor the purpose of enhancing their adhesiveness to resist film. As anexample of a suitable agent for conferring hydrophobicity onto thosesubstrates, 1,1,1,3,3,3-hexamethyldisilazane (HMDS) can be given.

[0196] The suitable thickness of a resist film coated on a substrate isin a range of about 0.1 to about 10 μm, and the thickness from about 0.1μm to about 1.5 μm is recommended in the case of ArF exposure.

[0197] It is desirable for the resist film coated on a substrate toundergo pre-bake for about 30-300 seconds at about 60-160° C. The lowerthe pre-bake temperature and the shorter the pre-bake time, the greaterthe increase in quantity of solvent remaining in the resist film; as aresult, bad influences, e.g., deterioration in the adhesiveness, aremore liable to be caused. In the opposite case where the pre-baketemperature is higher and the pre-bake time is shorter than theforegoing limits, troubles, such as the decomposition of components ineach photosensitive resin composition, such as a binder and a photo-acidgenerator, tend to be caused.

[0198] For radiation exposure of resist films after pre-bake,commercially available ultraviolet exposure apparatus, X-ray exposureapparatus, electron-beam exposure apparatus, KrF excimer exposureapparatus, ArF excimer exposure apparatus, F₂ excimer exposure apparatusand so on can be employed. In particular, the exposure apparatus usingArF excimer laser as light source is advantageous to the presentinvention.

[0199] The post-exposure bake is carried out for the purpose of causingthe elimination of protective groups by the use of acids as catalyst,the disappearance of standing wave, the diffusion of acid generators inresist film, and so on. This post-exposure bake can be effectedsimilarly to the pre-exposure bake. For instance, the baking temperatureis in the range of about 60 to 160° C., preferably about 90 to 150° C.

[0200] Examples of a developer which can be used for the presentphotosensitive resin compositions include aqueous solutions of variousalkalis, such as inorganic alkalis (e.g., sodium hydroxide, potassiumhydroxide, sodium carbonate, sodium silicate, aqueous ammonia), primaryamines (e.g., ethylamine, n-propylamine), secondary amines (e.g.,diethylamine, di-n-butylamine), tertiary amines (e.g., triethylamine,methyldiethylamine), alcoholamines (e.g., dimethylethanolamine,triethanolamine), quaternary ammonium salts (e.g., tetramethylammoniumhydroxide (TMAH), tetraethylammonium hydroxide (TEAH),trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammoniumhydroxide, trimethylhydroxyethylammonium hydroxide), and cyclic amines(e.g., pyrrole, piperidine, 1,8-diazabicyclo-[5.4.0]-7-undecene,1,5-diazabicyclo-[4.3.0]-5-nonane).

[0201] To the foregoing aqueous alkaline solutions, hydrophilic organicsolvents, such as alcohols and ketones, nonionic surfactants, anionicsurfactants, cationic surfactants, anti-foaming agents and so on mayfurther be added in their respective proper amounts. Those additives areadded for not only betterment of resist characteristics but also otherpurposes of, e.g., elevating the adhesiveness to a substrate, reducingthe amount of a developer used and lessening the defects arising fromair bubbles at the time of development.

[0202] Now, the present invention will be illustrated in greater detailby reference to the following examples, which are not to be consideredas limiting on or determinative of the scope of this invention.

SYNTHESIS EXAMPLE 1 Synthesis of Polymer A

[0203] The hydride of ring-opening polymerization product of thenorbornene derivative disclosed in Example 4 of JP-A-9-244247 (havingthe constitutional repeating unit illustrated below) was synthesized inaccordance with the method disclosed in European Patent No. 0,789,278(weight-average molecular weight: 22,000).

SYNTHESIS EXAMPLE 2 Synthesis of Polymer B

[0204] The hydride of ring-opening polymerization product of thenorbornene derivative disclosed in Example 1 of JP-A-9-244247 (havingthe constitutional repeating unit illustrated below) was synthesized inaccordance with the method disclosed in European Patent No. 0,789,278(weight-average molecular weight: 17,000).

SYNTHESIS EXAMPLE 3 Synthesis of Polymer C

[0205] The copolymer of norbornene, maleic anhydride, t-butylacrylateand acrylic acid (having the following constitutional repeating units)was synthesized in accordance with the method disclosed in Example 7 ofJP-A-10-10739 (weight-average molecular weight: 17,000; ratio betweenthe repeating units: 50/25/25 by mole).

SYNTHESIS EXAMPLE 4 Synthesis of Polymer D

[0206] The copolymer of adamantyl methacrylate and t-butylacrylate(having the following constitutional repeating units) was synthesized inaccordance with the method disclosed in Example 1 of JP-A-7-234511(weight-average molecular weight: 5,000; ratio between the repeatingunits: 58/42 by mole).

SYNTHESIS EXAMPLE 5 Synthesis of Acid-decomposable Low MolecularCompound

[0207] (Compound a):

[0208] The mixture of 122.7 g (0.3 mole) of cholic acid and 120 ml ofthionyl chloride was refluxed for 1 hour. After removal of excessthionyl chloride, the solid obtained was dissolved in 150 ml oftetrahydrofuran. Thereto, 40 g (0.35 mole) of potassium-t-butoxide wasadded little by little. The resulting mixture was refluxed for 6 hours,and then cooled. The reaction mixture thus prepared was poured intowater to deposit a solid matter. The solid matter was filtered off,washed with water, and then dried under reduced pressure. Thus obtainedcrude product was recrystallized from n-hexane to give t-butyl cholate(having the following structural formula) in a 70% yield.

SYNTHESIS EXAMPLE 6 Synthesis of Polymer E

[0209] Polymer E was synthesized according to Synthesis Example 1 ofJP-A-6-308734. More specifically, 30 g of poly(hydroxystyrene) wasdissolved in tetrahydrofuran, and admixed with 10 g of potassiumt-butoxide. Thereto, 60 g of di-t-butyl dicarbonate was further addeddropwise at 0° C. with stirring, and therein the reaction was run for 4hours. At the conclusion of the reaction, the reaction solution wasdripped into water, thereby precipitating a resinous matter. Theresinous matter was put in a vacuum desiccator and dried at 50° C. forone night. The resin obtained (Polymer E) had Mw of 15,000. As for thestructure thereof, it was confirmed by the NMR measurement that 29% ofthe hydrogen atoms of the phenolic hydroxy groups were replaced byt-butoxycarbonyl groups.

EXAMPLES 1A TO 6A AND COMPARATIVE EXAMPLES 1A TO 5A Preparation ofPhotosensitive Resin Compositions

[0210] The ingredients set forth in Table 1, namely the Polymer A, B, Cor D synthesized in Synthesis Example 1, 2, 3 or 4 respectively,triphenylsulfonium triflate (PAG-1) as a photo-acid generator, thecompound synthesized in Synthesis Example 5 (Compound a) as anacid-decomposable low molecular compound, a nitrogen-containing basiccompound, a surfactant, and propylene glycol monomethyl ether acetate asa solvent, were mixed together. The dotted line mark in Table 1 meansthat the corresponding ingredient was not used.

[0211] After mixing the foregoing ingredients together, the mixtureobtained was subjected to filtration with a 0.1 μm Teflon filter,thereby preparing each photosensitive resin composition.

[0212] The following are the amounts of ingredients used: Polymer A, B,C or D   10 g Photo-acid generator 0.06 g Acid-decomposable lowmolecular compound 0.25 g Nitrogen-containing basic compound 0.04 gSurfactant 0.05 g Solvent 57.4 g

[0213] The thus prepared photosensitive resin compositions were eachexamined for number of development defects and resist image quality inaccordance with the following evaluation methods respectively. Theevaluation results of the development defects are shown in Table 2, andthose of image quality are shown in Table 3.

Evaluation of Development Defects

[0214] (1) Development Defects I:

[0215] Each photosensitive resin composition was coated uniformly on ahexamethyldisilazane-treated silicon substrate by means of a spincoater, and dried by 90-second heating on a 120° C. hot plate to beformed into a 0.50 μm-thick resist film. This resist film was exposed toArF excimer laser beams via a mask. Immediately after the exposure, theresist film was heated for 90 seconds on a 110° C. hot plate. Then, itwas developed with a 2.38% by weight aqueous solution oftetramethylammonium hydroxide for 60 seconds at 23° C., rinsed with purewater for 30 seconds, and then dried. Thus, contact hole patterns wereformed on each resist film, and the number of development defectsgenerated therein was counted (under the condition of threshold 12 andpixcel size of 0.39) with a KAL 2112 machine (produced by KAL TenkohlInc.).

[0216] (2) Development Defects II:

[0217] The number of development defects was examined by the same methodas adopted for the examination of the foregoing development defects I,except that each resist film underwent no exposure.

Evaluation of Image Quality

[0218] Each photosensitive resin composition was formed into a 0.50μm-thick resist film, and further subjected sequentially to exposure,heating, development, rinsing and drying steps under the same conditionsas in the case of evaluating the development defects I mentioned above.Each of the thus processed resist films was examined for thickness bymeans of a film thickness gauge, and thereby the residual film rate[(film thickness after processing/film thickness before processing)×100]was determined.

[0219] Further, the pattern profile was examined by observing the 0.25μm line patterns formed on each resist film under a scanning electronmicroscope. In Table 3, the letter A is used for symbolizing arectangular profile, and the letter B for symbolizing another profile.TABLE 1 Formulation of Positive Photosensitive Resin Composition Acid-Nitro- Photo- Decompos- gen- acid able Low Contain- Poly- Gene-Molecular ing Basic Surfac- Sol- mer rator Compound Compound tant ventExample A PAG-1 — N-1 W-1 S-1 1a Example B PAG-1 — N-2 W-1 S-1 2aExample C PAG-1 — N-3 W-1 S-1 3a Example D PAG-1 — N-4 W-2 S-1 4aExample B PAG-1 Compound a N-1 W-2 S-1 5a Example C PAG-1 Compound a N-2W-3 S-1 6a Compar. A PAG-1 — — — S-1 Ex. 1a Compar. B PAG-1 — — W-1 S-1Ex. 2a Compar. C PAG-1 — N-3 — S-1 Ex. 3a Compar. D PAG-1 — N-4 W-4 S-1Ex. 4a Compar. B PAG-1 Compound a — — S-1 Ex. 5a

[0220] The symbols in Table 1 stand for the following compoundsrespectively;

[0221] PAG-1: triphenylsulfonium triflate

[0222] N-1: Hexamethylenetetramine

[0223] N-2: 1,5-Diazabicyclo[4.3.0]-5-nonene

[0224] N-3: 1,8-Diazabicyclo[5.4.0]-7-undecene

[0225] N-4: 1,4-Diazabicyclo[2.2.2]octane

[0226] W-1: Megafac F176 (produced by Dai-Nippon Ink & Chemicals Inc.)(fluorine-containing surfactant)

[0227] W-2: Megafac R08 (produced by Dai-Nippon Ink & Chemicals Inc.)(fluorine and silicon-containing surfactant)

[0228] W-3: Polysiloxane polymer KP-341 (produced by Shin-etsu ChemicalIndustry Co., Ltd.)

[0229] W-4: Polyoxyethylene nonyl phenyl ether

[0230] S-1: Propylene glycol monomethyl ether acetate TABLE 2 Number ofDevelopment Defects Development Development Defects I Defects II Example1a 4 11 Example 2a 2 5 Example 3a 5 15 Example 4a 4 7 Example 5a 0 2Example 6a 0 1 Comparative 62 340 Example 1a Comparative 36 130 Example2a Comparative 42 165 Example 3a Comparative 3 8 Example 4a Comparative23 35 Example 5a

[0231] TABLE 3 Image Quality of Resist Residual Film Rate (%) ProfileExample 1a 99.9 A Example 2a 99.7 A Example 3a 99.4 A Example 4a 99.2 AExample 5a 100.0 A Example 6a 100.0 A Comparative 99.2 A Example 1aComparative 99.0 A Example 2a Comparative 99.0 A Example 3a Comparative94.2 B Example 4a Comparative 99.2 A Example 5a

[0232] As can be seen from the results shown in Tables 2 and 3, all thephotosensitive resin compositions according to the present inventionproduced very few development defects and formed patterns having arectangular profile.

[0233] On the other hand, a lot of development defects were developed inthe cases of Comparative Examples 1 and 5 using neithernitrogen-containing basic compound (C) nor surfactant (D), ComparativeExample 2 using a surfactant (D) but no nitrogen-containing basiccompound (C) and Comparative Example 3 using a nitrogen-containing basiccompound (C) but no surfactant (D). In the case of Comparative Example 4using a surfactant other than the surfactants specified by the presentinvention, the development defects were relatively few but the resistprofile was not good.

EXAMPLES 7A TO 14A AND COMPARATIVE EXAMPLES 6A TO 7A Preparation ofPhotosensitive Resin Compositions

[0234] The ingredients set forth in Table 4, namely the Polymer B, C orD synthesized in Synthesis Example 2, 3 or 4 respectively, (PAG-1)recited above or triphenylsulfonium perfluorobutanesulfonate (PAG-2) asa photo-acid generator, the compound synthesized in Synthesis Example 5as an acid-decomposable low molecular compound and a combination ofnitrogen-containing basic compound, surfactant and solvent set forth inTable 4, were mixed in their respective proportions set forth in Table4. The dotted line mark in Table 4 means that the correspondingingredient was not used.

[0235] After the foregoing ingredients were mixed together, the mixtureobtained was subjected to filtration with a 0.1 μm Teflon filter,thereby preparing each photosensitive resin composition. In Table 5, theratio of Component (B) to Component (C) ((B)/(C) ratio) and the ratio ofComponent (A) to Component (D) ((A)/(D) ratio) in each photosensitiveresin composition are set forth. TABLE 4 Formulation of PositivePhotosensitive Resin Composition Nitrogen- Acid-decompos- containingPolymer Photo-acid able Compound Basic Com- Surfactant (A) Generator (B)(C) pound (D) (E) Solvent (F) Example 7a B 14.69 PAG-2 0.300 — — N-30.005 W-1 0.001 S-1 85.00 Example 8a B 13.34 PAG-1 0.150 Compound a 1.50N-2 0.008 W-1 0.001 S-3 86.49 Example 9a C 14.84 PAG-1 0.150 — — N-20.008 W-2 0.009 S-5/ 72.24/ S-6 12.74 Example 10a D 13.84 PAG-2 0.150Compound a 1.00 N-4 0.001 W-3 0.020 S-1/ 59.50/ S-2 25.50 Example 11a C14.55 PAG-2 0.450 — — N-2 0.003 W-1 0.001 S-3/ 59.50/ S-4 25.50Comparative C 14.42 PAG-1 0.087 — — N-3 0.057 — — S-1 85.44 Example 6aComparative D 14.83 PAG-1 0.150 — — N-4 0.008 W-4 0.015 S-3 85.00Example 7a Example 12a C 14.42 PAG-1 0.087 — — N-3 0.057 W-1 0.072 S-185.36 Example 13a B 13.27 PAG-2 0.150 Compound a 1.50 N-2 0.008 W-30.075 S-3 85.00 Example 14a D 14.25 PAG-1 0.750 — — N-2 0.002 W-3 0.001S-1 85.00

[0236] The symbols PAG-1, N-2, N-3, N-4, W-1, W-2, W-3, W-4 and S-1stand for the same compounds set forth in Table 1 respectively, and theother symbols stand for the following compounds respectively;

[0237] PAG-2: Triphenylsulfonium perfluorobutanesulfonate

[0238] S-2: Propylene glycol monomethyl ether

[0239] S-3: Ethyl lactate

[0240] S-4: Ethyl 3-ethoxypropionate

[0241] S-5: Propylene glycol monopropyl ether propionate

[0242] S-6: 2-Heptanone TABLE 5 Component Ratios in Photosensitive ResinComposition (B)/(C) ratio (A)/(D) ratio Example 7a 60.0 14690 Example 8a18.8 13340 Example 9a 18.8 1649 Example 10a 150.0 692 Example 11a 150.014550 Comparative Example 6a 1.5 — Comparative Example 7a 18.8 989Example 12a 1.5 200 Example 13a 18.8 177 Example 14a 375.0 14250

[0243] The thus prepared photosensitive resin compositions were eachexamined for number of development defects and resist image quality inaccordance with the following evaluation methods respectively. Theevaluation results of the development defects are shown in Table 6, andthose of image quality are shown in Table 7.

Evaluation of Development Defects

[0244] The evaluation of development defects was carried out by the samemethod as mentioned in Examples 1a-6a.

Evaluation of Image Quality

[0245] On a hexamethyldisilazane-treated silicon substrate, DUV-42(produced by Brewer Science Inc.) was coated uniformly in a thickness of600 Å with a spin coater, dried for 90 seconds on a 100° C. hot plate,and further heated for 240 seconds at 190° C., thereby forming areflection inhibitive film. On this reflection inhibitive film, eachphotosensitive resin composition was coated with a spin coater and driedfor 90 seconds at 130° C. to be formed into a 0.50 μm-thick resist film.Further, this resist film was exposed to ArF excimer laser beams via amask. Immediately after the exposure, the resist film was heated for 90seconds on a 130° C. hot plate. Then, it was developed with an aqueoussolution of tetramethylammonium hydroxide for 60 seconds at 23° C.,rinsed with pure water for 30 seconds, and then dried. Thus, linepatterns were formed on each resist film. Thereafter, each of the thusprocessed resist films was examined for thickness by means of a filmthickness gauge, and the residual film rate was determined bysubstituting this thickness value in the equation mentionedhereinbefore.

[0246] Further, the pattern profile was examined by observing the 0.25μm line patterns formed on each resist film under a scanning electronmicroscope. In Table 7, the letter A is used for symbolizing arectangular profile, the letter C for symbolizing a tapered profile, andthe letter B for a profile with a T shape.

[0247] The sensitivity was expressed in terms of the exposure amountrequired for reproducing the 0.25 μm mask patterns.

[0248] The resolution was represented by the threshold resolutionachieved under the exposure amount enabling the reproduction of the 0.25μm mask patterns.

[0249] With respect to the developability, the letter A is used forsymbolizing the case where no development residues was observed, and theletter B for symbolizing the case where development residues were moreor less observed. TABLE 6 Number of Development Defects DevelopmentDevelopment Defects I Defects II Example 7a 0 1 Example 8a 0 0 Example9a 0 1 Example 10a 0 0 Example 11a 1 0 Comparative Example 6a 42 165Comparative Example 7a 4 9 Example 12a 5 7 Example 13a 1 2 Example 14a 67

[0250] TABLE 7 Image Quality of Resist Residual Sensi- Resolu- Film Ratetivity tion Pro- Develop- (%) (mJ/cm²) (μm) file ability Example 7a 99.921 0.14 A A Example 8a 100.0 20 0.14 A A Example 9a 99.9 28 0.16 A AExample 10a 100.0 17 0.14 A A Example 11a 99.9 15 0.15 A A Compar. Ex.6a 99.0 64 0.17 A A Compar. Ex. 7a 94.3 36 0.18 C A Example 12a 99.4 590.17 A B Example 13a 100.0 20 0.18 A B Example 14a 98.2 16 0.20 B A

[0251] As can be seen from the results shown in Tables 6 and 7, thepresent compositions wherein the particular components were used withinthe special proportion ranges provided resist films causing very fewdevelopment defects, forming patterns with a rectangular profile andhaving excellent sensitivity, resolution and developability.

[0252] In accordance with embodiments of the present invention, thepositive photosensitive resin compositions cause very few developmentdefects, showed satisfactorily high sensitivity, resolution anddevelopability and ensure excellent pattern profiles when ArF excimerlaser beams are used as exposure light source. Therefore, they areeffective in forming fine patterns meeting the requirements for theproduction of semiconductor elements.

EXAMPLES 1B TO 7B AND COMPARATIVE EXAMPLES 1B To 7B Preparation ofPhotosensitive Resin Compositions

[0253] The ingredients set forth in Table 8, namely the Polymer A, B, C,D or E synthesized in Synthesis Example 1, 2, 3, 4 or 6 respectively,triphenylsulfonium triflate (PAG-1) as a photo-acid generator, thecompound synthesized in Synthesis Example 5 (Compound a) as anacid-decomposable low molecular compound and a combination ofnitrogen-containing basic compound, surfactant and solvents set forth inTable 8, were mixed together. The dotted line mark in Table 8 means thatthe corresponding ingredient was not used.

[0254] After mixing the foregoing ingredients together, the mixtureobtained was subjected to filtration with a 0.1 μm Teflon filter,thereby preparing each photosensitive resin composition.

[0255] The following are the amounts of ingredients used: Polymer A, B,C, D or E   10 g Photo-acid generator 0.06 g Acid-decomposable lowmolecular compound 0.25 g Nitrogen-containing basic compound 0.04 gSurfactant 0.05 g Solvents 57.4 g

[0256] The thus prepared photosensitive resin compositions were eachexamined for numbers of development defects I and II in accordance withthe foregoing evaluation methods respectively. The evaluation resultsare shown in Table 9. TABLE 8 Formula of Positive Photosensitive ResinComposition Acid- Photo- decompos- Nitrogen Solvents acid able lowcontain- Sur- (ratio Poly- gene- molecular ing basic fac- by mer ratorcompound compound tant weight) Example A PAG-1 — N-1 W-1 S-2/S-3 1b(70/30) Example B PAG-1 — N-2 W-1 S-2/S-3 2b (80/20) Example C PAG-1 —N-3 W-2 S-2/S-3/ 3b S-4 (75/ 20/5) Example D PAG-1 Compound a N-4 W-3S-2/S-3/ 4b S-5 (75/ 20/5) Example A PAG-1 Compound a N-3 W-2 S-2/S-3/5b S-6 (82/ 15/3) Example B PAG-1 — N-3 W-3 S-1/S-3/ 6b S-6 (65/ 35/5)Example C PAG-1 Compound a N-1 W-1 S-2/S-3/ 7b S-6 (60/ 30/10) Compar. APAG-1 — — — S-2/S-3 Ex. 1b (70/30) Compar. B PAG-1 — — W-1 S-1/S-3 Ex.2b (80/20) Compar. A PAG-1 — N-1 — S-2/S-3 Ex. 3b (70/30) Compar. APAG-1 — N-1 W-3 S-2 Ex. 4b Compar. C PAG-1 — N-3 W-4 S-2/S-3 Ex. 5b(70/30) Compar. E PAG-1 — — — S-2/S-3 Ex. 6b (50/50) Compar. E PAG-1 — —W-1 S-2 Ex. 7

[0257] The symbols used in Table 8 stand for the following compoundsrespectively;

[0258] S-2: Ethyl lactate

[0259] S-3: butyl acetate

[0260] S-4: γ-Butyrolactone

[0261] S-5: Propylene carbonate

[0262] S-6: Ethylene carbonate

[0263] The other symbols stand for the same compounds as defined in thepreceding Examples, respectively. TABLE 9 Number of Development DefectsDevelopment Development Defects I Defects II Example 1b 3 3 Example 2b 34 Example 3b 1 2 Example 4b 0 0 Example 5b 0 0 Example 6b 1 0 Example 7b0 0 Compar. Ex. 1b 68 362 Compar. Ex. 2b 43 165 Compar. Ex. 3b 35 76Compar. Ex. 4b 11 7 Compar. Ex. 5b 7 17 Compar. Ex. 6b 24 38 Compar. Ex.7b 17 14

[0264] As can be seen from the results shown in Table 9, the number ofeach type of development defects was very small in every case of thepresent photosensitive resin compositions. In particular, the resultswere entirely satisfactory in the cases of the compositions using thethird solvent (c) (Examples 3b-7b).

[0265] In the cases of comparative photosensitive resin compositions, onthe other hand, the development defects were considerably large innumber. In particular, the number of development defects roughly doubledin the case of Comparative Example 4b using ethyl lactate alone as thesolvent, compared with the present cases of using mixed solvent systems.In the case of Comparative Example 5b using a surfactant other thanthose specified by the present invention, the number of developmentdefects was more than twice those in the present cases of using the samemixed solvent system.

EXAMPLES 1C TO 7C AND COMPARATIVE EXAMPLES 1C TO 7C Preparation ofPhotosensitive Resin Compositions

[0266] The ingredients set forth in Table 10, namely the Polymer A, B,C, D or E synthesized in Synthesis Example 1, 2, 3, 4 or 6 respectively,triphenylsulfonium triflate (PAG-1) as a photo-acid generator, thecompound synthesized in Synthesis Example 5 (Compound a) as anacid-decomposable low molecular compound and a combination ofnitrogen-containing basic compound, surfactant and solvents set forth inTable 10, were mixed together. The dotted line mark in Table 10 meansthat the corresponding ingredient was not used.

[0267] After mixing the foregoing ingredients together, the mixtureobtained was subjected to filtration with a 0.1 μm Teflon filter,thereby preparing each photosensitive resin composition.

[0268] The following are the amounts of ingredients used: Polymer A, B,C, D or E   10 g Photo-acid generator 0.06 g Acid-decomposable lowmolecular compound 0.25 g Nitrogen-containing basic compound 0.04 gSurfactant 0.05 g Solvents 57.4 g

[0269] The thus prepared photosensitive resin compositions were eachexamined for numbers of development defects I and II in accordance withthe foregoing evaluation methods respectively. The evaluation resultsare shown in Table 11. TABLE 10 (Formulation of Positive PhotosensitiveResin Composition) Acid- Photo- decompos- Nitrogen Solvents acid ablelow contain- Sur- (ratio Poly- gene- molecular ing basic fac- by merrator compound compound tant weight) Example A PAG-1 — N-1 W-1 S-2/S-71c (70/30) Example B PAG-1 — N-2 W-1 S-2/S-7 2c (80/20) Example C PAG-1— N-3 W-2 S-2/S-7/ 3c S-4 (75/ 20/5) Example D PAG-1 Compound a N-4 W-3S-2/S-7/ 4c S-5 (75/ 20/5) Example A PAG-1 Compound a N-3 W-2 S-2/S-7/5c S-6 (82/ 15/3) Example B PAG-1 — N-3 W-3 S-2/S-7/ 6c S-6 (65/ 35/5)Example C PAG-1 Compound a N-1 W-1 S-2/S-7/ 7c S-6 (60/ 30/10) Compar. APAG-1 — — — S-2/S-7 Ex. 1c (70/30) Compar. B PAG-1 — — W-1 S-2/S-7 Ex.2c (80/20) Compar. A PAG-1 — N-1 — S-2/S-7 Ex. 3c (70/30) Compar. APAG-1 — N-1 W-3 S-2 Ex. 4c Compar. C PAG-1 — N-3 W-4 S-2/S-7 Ex. 5c(70/30) Compar. E PAG-1 — — — S-2/S-7 Ex. 6c (50/50) Compar. E PAG-1 — —W-1 S-2 Ex. 7c

[0270] The symbols used in Table 10 stand for the following compoundsrespectively;

[0271] S-2: Ethyl lactate

[0272] S-7: Ethyl 3-ethoxypropionate

[0273] S-4: γ-Butyrolactone

[0274] S-5: Propylene carbonate

[0275] S-6: Ethylene carbonate

[0276] The other symbols stand for the same compounds as defined in thepreceding Examples, respectively. TABLE 11 Number of Development DefectsDevelopment Development Defects I Defects II Example 1c 2 3 Example 2c 33 Example 3c 1 1 Example 4c 0 0 Example 5c 0 0 Example 6c 1 0 Example 7c0 0 Compar. Ex. 1c 60 327 Compar. Ex. 2c 33 145 Compar. Ex. 3c 35 83Compar. Ex. 4c 11 7 Compar. Ex. 5c 5 10 Compar. Ex. 6c 21 28 Compar. Ex.7c 17 14

[0277] As can be seen from the results shown in Table 11, the number ofeach type of development defects was very small in every case of thepresent photosensitive resin compositions. In particular, there were noor very few, if any, development defects in the cases of Examples 3c-7cusing three kinds of solvents.

[0278] In the cases of comparative photosensitive resin compositions, onthe other hand, the development defects were markedly large in number.In particular, the number of development defects in the case ofComparative Example 4c using ethyl lactate alone as the solvent was morethan twice that in the case of Example 1c.

[0279] In the case of Comparative Example 5c using a surfactant otherthan those specified by the present invention, the number of developmentdefects roughly doubled, compared with the case of Example 1c.

[0280] The positive photosensitive resin compositions according to thepresent invention have excellent resist characteristics, coatingsuitability, storage stability and safety. In particular, they have anadvantage of being free of the development-defects problem. Therefore,the present positive photosensitive resin compositions are especiallyuseful for the lithography utilizing ArF excimer laser beams as exposurelight source.

[0281] While the invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof.

What is claimed is:
 1. A positive photosensitive resin compositioncomprising: (A) a polymer which has alicyclic hydrocarbon skeletons anddecomposes by the action of an acid to thereby become alkali-soluble,(B) a compound which generates an acid upon irradiation with actinicrays, (C) a nitrogen-containing basic compound, and (D) at least one ofa fluorine-containing surfactant and a silicon-containing surfactant. 2.A positive photosensitive resin composition comprising: (A) a polymerwhich has bridged alicyclic hydrocarbon skeletons and decomposes by theaction of an acid to thereby become alkali-soluble, (B) a compound whichgenerates an acid upon irradiation with actinic rays, (C) anitrogen-containing basic compound, (D) a fluorine and/orsilicon-containing surfactant, and (E) a solvent; wherein the ratio of(B) to (C) by weight is from 5 to 300 and the ratio of (A) to (D) byweight is from 500 to 20,000.
 3. The positive photosensitive resincomposition as described in claim 1, further comprising a low molecularacid-decomposable compound which has a molecular weight of 2,000 orbelow and a group capable of decomposing under the action of an acid toincrease its solubility in alkali.
 4. The positive photosensitive resincomposition as described in claim 3, wherein the content of the lowmolecular acid-decomposable compound is from 0.5 to 20.0 parts by weightper 100 parts by weight of the total solids of the composition.
 5. Thepositive photosensitive resin composition as described in claim 1,wherein the compound as Component (B) is an onium salt.
 6. The positivephotosensitive resin composition as described in claim 1, wherein thenitrogen-containing basic compound as Component (C) is an organic amine.7. The positive photosensitive resin composition as described in claim2, wherein the solvent as Component (E) comprises at least one solventselected from the group consisting of ethyl lactate, propylene glycolmonomethyl ether acetate, propylene glycol monomethyl ether, propyleneglycol monomethyl ether propionate, methyl 3-methoxypropionate, ethyl3-ethoxypripionate and 2-heptanone in an amount of at least 70% byweight based on the total solvent.
 8. The positive photosensitive resincomposition as described in claim 1, wherein the actinic rays are deepultraviolet rays having wavelengths of 220 nm or shorter.
 9. A positivephotosensitive resin composition comprising: (A) a polymer which hasalicyclic hydrocarbon skeletons and decomposes under the action of anacid to become alkali-soluble, (B) a compound which generates an acidupon irradiation with actinic rays, (C) a nitrogen-containing basiccompound, (D) a fluorine and/or silicon-containing surfactant, and (E) asolvent comprising as a first solvent at least one solvent selected fromthe following group (a) in an amount of 60 to 90% by weight based on thetotal solvent and as a second solvent a solvent selected from thefollowing group (b) in an amount of 10 to 40% by weight to the totalsolvent; the group (a) consisting of ethyl lactate, propylene glycolmonomethyl ether acetate, propylene glycol monomethyl ether propionate,methyl 3-methoxypropionate and-ethyl 3-ethoxypropionate, and the group(b) consisting of solvents having a viscosity of not higher than 1centipoise at 20° C.
 10. The positive photosensitive resin compositionas described in claim 9, wherein the solvent as Component (E) furthercomprises as a third solvent (c) a solvent having a boiling point of notlower than 180° C. and a solubility parameter of at least 12 in anamount of 1 to 20% by weight based on the total solvent.
 11. Thepositive photosensitive resin composition as described in claim 10,wherein the third solvent (c) is at least one solvent selected from thegroup consisting of γ-butyrolactone, ethylene carbonate and propylenecarbonate.
 12. The positive photosensitive resin composition asdescribed in claim 9, wherein the number of carbon atoms forming each ofthe alicyclic hydrocarbon skeletons present in the polymer as Component(A) is from 5 to
 25. 13. The positive photosensitive resin compositionas described in claim 9, wherein the nitrogen-containing basic compoundas Component (C) is at least one compound selected from the groupconsisting of organic amines, basic ammonium salts and basic sulfoniumsalts.
 14. The positive photosensitive resin composition as described inclaim 9, further comprising a low molecular acid-decomposabledissolution inhibitive compound which has a molecular weight of 2,000 orbelow and a group capable of decomposing under the action of an acid toincrease its solubility in alkali.
 15. The positive photosensitive resincomposition as described in claim 9, wherein the actinic rays are deepultraviolet rays having wavelengths of 220 nm or shorter.
 16. A positivephotosensitive resin composition comprising: (A) a polymer has alicyclichydrocarbon skeletons and decomposes under the action of an acid tobecome alkali-soluble, (B) a compound which generates an acid uponirradiation with actinic rays, (C) a nitrogen-containing basic compound,(D) at least one of a fluorine-containing surfactant and asilicon-containing surfactant, and (E) a solvent comprising (a) ethyllactate in an amount of 60 to 90% by weight based on the total solventand (b) ethyl 3-ethoxypropionate in an amount of 10 to 40% by weightbased on the total solvent.
 17. The positive photosensitive resincomposition as described in claim 16, wherein the solvent as Component(E) further comprises a solvent (c) having a boiling point of not lowerthan 180° C. and a solubility parameter of at least 12 in an amount of 1to 20% by weight based on the total solvent.
 18. The positivephotosensitive resin composition as described in claim 17, wherein thesolvent (c) is at least one solvent selected from the group consistingof γ-butyrolactone, ethylene carbonate and propylene carbonate.
 19. Thepositive photosensitive resin composition as described in claim 16,wherein the number of carbon atoms forming each of the alicyclichydrocarbon skeletons present in the polymer as Component (A) is from 5to
 25. 20. The positive photosensitive resin composition as described inclaim 16, wherein the nitrogen-containing basic compound as Component(C) is at least one compound selected from the group consisting oforganic amines, basic ammonium salts and basic sulfonium salts.
 21. Thepositive photosensitive resin composition as described in claim 16,further comprising a low molecular acid-decomposable dissolutioninhibitive compound which has a molecular weight of 2,000 or below and agroup capable of decomposing under the action of an acid to increase itssolubility in alkali.
 22. The positive photosensitive resin compositionas described in claim 16, wherein the actinic rays are deep ultravioletrays having wavelengths of 220 nm or shorter.